This invention relates to polyurethane/urea matrices for the delivery of active agents. The polyurethane/urea matrices are prepared by a process of reacting a urethane prepolymer with an aromatic diamine chain extender in the presence of an active agent such as a fragrance agent or an insect repellant agent. This invention also relates to a process for making the polyurethane/urea matrices as well as to products in which the polyurethane/urea matrices may be incorporated.
Polymeric matrices for delivering fragrances or other active agents are known in the art but suffer from the shortcomings of toxicity, cloudiness, instability, and the fractionation of the active components during delivery. Polyurethane/urea elastomers are generally prepared by first reacting an aromatic isocyanate with a polyol to form a prepolymer and then chain extending the prepolymer with an aromatic diamine to form the elastomer. Conventional polymeric matrices for delivering actives generally intermix an active agent into a finished polyurethane/urea elastomer.
U.S. Pat. No. 4,423,099 (Mueller et al.) discloses a non-uniform substantially water-insoluble inter-penetrating polymer blend composition comprising a water-swellable first polymer substrate interpenetrated in a gradient substantially normal to the substrate surface by a less permeable condensation second polymer to form a diffusion rate controlling membrane therein. The water-swellable first polymer may be cellulose or a homopolymer or copolymer containing vinyl alcohol, acrylamide, hydroxyalkylacrylate or methacrylate, vinylpyrrolidone, or hydroxyalkylvinyl ether, maleate, or fumarate or a polyethyleneoxide diol containing polycondensate. The less permeable condensation second polymer may be an aliphatic or aromatic polyurethane, polyester, polyamide, polyimide, polyurea, or polyimine. The compositions are said to be useful as polymers with reduced permeabilities for water and organic solvents and therefore for the controlled delivery of active ingredients such as fragrances and bio-affecting agents into air or aqueous environments, or in membrane separation processes.
U.S. Pat. No. 4,842,761 (Rutherford) discloses a composition for laundering textiles which comprises a detergent composition and a particulate fragrance-bearing polymer comprising a water-soluble normally solid polymer, a water-insoluble normally solid polymer, and a perfume composition. A portion of the perfume composition is incorporated in the water-soluble polymer and a portion is incorporated in the water-insoluble polymer. The water-soluble polymer and the water-insoluble polymer are physically associated with each other such that one is in the form of discrete entities in a matrix of the other. The matrix substantially comprises the surface of the particle. The water-soluble polymer may be a water-soluble polyurethane and the water-insoluble polymer may be a thermoplastic polyurethane. The composition is made by incorporating a perfume composition into a water-soluble polymer, incorporating an olfactory composition into a water-insoluble polymer, intermixing the water-soluble polymer and the water-insoluble polymer under high-shear to provide discrete entities of one polymer in a matrix of the other polymer.
U.S. Pat. No. 4,880,851 (Yamamoto""851) and U.S. Pat. No. 5,075,350 (Yamamoto""350) disclose a method for preparing a composition having a perfume encapsulated in a matrix of polymer. The method comprises adding an acid catalyst for sol-gel methods to an aqueous mixture of alkoxides of metal, silicon, or phosphorus, and a perfume to hydrolyze the alkoxides. A base catalyst for sol-gel methods is added to the reaction mixture to condense the hydrolysate to form a polymer and thereby encapsulate the perfume in the matrix of the polymer. The base catalyst is N,N-dimethylbenzylamine, tributylamine, tri-n-propylamine, tri-pentyl amine, tri-propargyl amine, N,N,N-trimethylethylenediamine, or tri-n-hexylamine.
U.S. Pat. No. 4,980,392 (Yamamoto""392) and U.S. Pat. No. 5,387,622 (Yamamoto""622) disclose a method for preparing a composition comprising a perfume encapsulated in a matrix of conjugated polymer. The composition is prepared by adding an acid catalyst for sol-gel methods to a reaction mixture comprising water, an alkoxide selected from metal alkoxides, phosphorus alkoxides, and tetraethoxysilane, a silane coupling agent, and a perfume substance, to hydrolyze the alkoxide and the silane coupling agent, to thereby form a hydrolysate. A base catalyst for sol-gel methods is added to the reaction mixture to condense the hydrolysate to form a conjugated polymer, thereby encapsulating the perfume substance in the matrix of the conjugated polymer.
U.S. Pat. No. 4,987,161 (Yamamotol""161) and U.S. Pat. No. 4,988,744 (Yamamoto""744) disclose a method for preparing a composition comprising a perfume encapsulated in a matrix of conjugated polymer. The method comprises adding an acid catalyst for sol-gel methods to a reaction mixture comprising water, an alkoxide selected from the group consisting of metal alkoxides, phosphorus alkoxides, and tetraethoxysilane, a silane coupling agent, and a perfume substance to hydrolyze the alkoxide, and the silane coupling agent to forming a hydrolysate. An organic monomer selected from the group consisting of acrylic acid, methacrylic acid, dimethyl formamide, acrylonitrile, styrene, methyl acrylate, ethyl acrylate, methyl methacrylate and ethyl methacrylate, is added to the reaction mixture. A base catalyst for sol-gel methods is then added to the reaction mixture followed by irradiating the reaction mixture so that condensation of the hydrolysate occurs with the polymerization of the organic monomer and the hydrolysate of the silane coupling agent to form a conjugated polymer, thereby encapsulating the perfume substance in the matrix of the conjugated polymer.
U.S. Pat. No. 5,093,182 (Ross) discloses a fragrance-releasing, image-displaying article comprising a substrate having deposited thereon a printed image and a fragrance-containing coating composition. The composition comprises an unencapsulated fragrance oil having dissolved therein a sustained-release agent selected from the group consisting of ethyl cellulose, cellulose acetate proprionate, and ethyl hydroxy ethyl cellulose.
U.S. Pat. No. 5,391,420 (Bootinan et al. ""420) discloses a fragrance-laden pouch for sampling fragrances. The pouch comprises (a) a bottom barrier film member; (b) a top barrier film member joined to the bottom barrier film member to form an enclosure; (c) a fragrance-laden polymer contained within the enclosure in contact with the top and bottom barrier film members; and (d) means for separating the top barrier film member from the bottom barrier film member to permit release of fragrance from the enclosure. The polymer is a modified cellulosic selected from the group consisting of ethyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, and the sodium salt of carboxymethyl cellulose.
U.S. Pat. No. 5,569,683 (Bootman et al.""683) discloses a gel comprising a multi-component scented mixture disposed in a polymer matrix comprising the polymerization product of one or more ethylenically unsaturated monomers. The monomers are selected such that the gel has sufficient mechanical integrity to retain its shape under ambient conditions, releases the components of the scented mixture in a manner that substantially preserves the scent of the mixture upon release, and is adapted for incorporation in a container manufactured according to a continuous process in a high speed line. The polymer is derived from an ethylenically unsaturated monomer such as acrylate or methacrylate.
U.S. Pat. No. 5,858,385 (Sirkar et al.) discloses a controlled release device comprising a microporous membrane consisting of a hollow fiber having sealed ends or a film attached to a flat-ended reservoir. The pores extending through the microporous membrane wall are filled with water or an organic solvent and the fiber lumen or reservoir is filled with an organic solvent or water and a selected pest-control substance or fragrance so that the pest-control substance or fragrance in the fiber lumen or reservoir partitions into the water or organic solvent in the pores and diffuses through the water or organic solvent in the pores and out of the microporous membrane.
U.S. Pat. No. 5,965,276 (Shlenker et al.) discloses a latex article having a biocide barrier. The barrier comprises a first layer of cured liquid latex free of biocide, a second layer of a biocide effective as a coagulant for liquid latex, and a third layer of cured liquid latex free of biocide.
U.S. Pat. No. 4,786,703 (Starner et al.) discloses a process for producing a reaction product comprising a prepolymer suited for producing polyurethane/urea elastomers. The method comprises reacting a toluenediisocyanate with a long chain polyol to produce a prepolymer and then reacting the prepolymer with an aromatic diamine to form a polyurethane/urea elastomer. The improvement comprises reacting an isomer of 2,4- or 2,6-toluene diisocyanate with a long chain diol at a temperature from about 0xc2x0 C. to 90xc2x0 C., and at a mole ratio of toluenediisocyanate to long chain diol from 4 to 20:1, to form a prepolymer such that at least about 90% of such prepolymer consists of a prepolymer of two moles toluenediisocyanate per mole of long chain diol. Unreacted toluenediisocyanate is then removed from the reaction product to result in a prepolymer level of less than about 0.15%.
While the above disclosures describe the preparation of polymeric matrices for delivering fragrances, none of the above disclosures describe methods that are entirely satisfactory. None of the above disclosures describe the preparation of polymeric matrices for delivering active agents which incorporate the active in the reaction between a polyurethane prepolymer and a curative amine. The present invention provides such improved polymeric matrices for delivering actives without the disadvantages characteristic of previously known compositions.